JP2003167491A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning system which can prevent the phenomenon called as one-side chipping caused in a system using an a-Si photoreceptor and a large amount of an abrasive, and to provide a cleaning system for an a-Si photoreceptor having favorable cleaning property without increasing the cost compared to conventional systems or without causing melt sticking of a toner on a photoreceptor, cleaning failure or slipping. <P>SOLUTION: The cleaning blade assembled in the cleaning device of an image forming device and to be pressed in contact with a rotating electrostatic latent image carrying body is composed of a urethane rubber base material and a hardened layer on the surface formed by surface treating the base material with an isocyanate compound. At least the part of the cleaning blade in contact with an electrostatic latent image carrying body is impregnated with an isocyanate compound and then hardened by heating to form the hardened layer. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as an electrophotographic copying machine and an information recording apparatus, and develops a latent image formed on an electrostatic latent image carrier with a developer. The present invention relates to a cleaning device that recovers a developer remaining on the surface of an electrostatic latent image carrier after transferring an agent image onto a transfer paper.

[0002]

2. Description of the Related Art Image formation in which a step of transferring a toner image to a transfer material by abutting a sheet-like transfer material such as paper on an electrostatic latent image carrier having a toner image electrostatically formed on its surface is repeated. In the apparatus, since not all the toner on the electrostatic latent image carrier side is transferred to the transfer material during transfer, it is necessary to remove the residual toner on the surface of the electrostatic latent image carrier at each transfer. is there.

As a cleaning means for this purpose, a cleaning blade made of an elastic member such as rubber has been conventionally used to press the electrostatic latent image carrier at the position after transfer to scrape off the residual toner, and more particularly, magnetic toner. As a suitable means when using the above, a magnet roller is commonly used.

As a material for the above-mentioned cleaning blade, polyurethane rubber having a peak temperature of tan δ of its viscoelastic property of 1 ± 10 ° C. has been used. The cleaning blade having such characteristics has a high impact resilience and a high rubber elasticity near the surface temperature of the photoconductor. Therefore, when the blade is pressed against the photosensitive drum, the width in which the blade is in contact with the photosensitive drum (hereinafter,
Stable nip width) and good cleaning property.

On the other hand, a photoconductor used in an electrophotographic copying machine.
As an (electrostatic latent image carrier), especially for black and white high speed copying machines,
Amorphous silicon (hereinafter a-
A photoconductor is used.

Although the a-Si photoconductor has high surface hardness and high durability, there is a problem that the surface of the photoconductor is not easily scraped. In the electrophotographic process, the toner developed on the photoconductor is transferred to a transfer material such as paper, but the toner left on the photoconductor without being transferred at that time is removed by the cleaning member. Therefore, the toner that cannot be completely removed is not a problem because it is usually scraped together with the surface of the photoconductor due to friction with the toner due to the subsequent development and transfer processes. However, since the a-Si photoconductor has high hardness, it is difficult to remove the surface of the a-Si photoconductor, and it is difficult to remove the residual toner.
A phenomenon referred to as “toner fusion” hereinafter occurs as the durability progresses particularly in a high temperature and high humidity environment.

When such toner fusion occurs, the blade having high repulsion elasticity used conventionally does not have the ability to remove the toner fusion, and the toner fusion further progresses.

Two measures have been taken to prevent such toner fusing: (1) inclusion of an abrasive as an external additive of the toner, (2) material of the cleaning blade And its viscoelastic property tan δ
Whose peak temperature is close to the surface temperature of the photoconductor is used.

In (1), the external additive component of the toner removed by the cleaning blade from the photosensitive drum after transfer causes the blade to come into contact with the photosensitive drum when the cleaning blade is pressed against the photosensitive drum. It accumulates in a wedge-shaped space adjacent to the part (hereinafter referred to as the nip part). In particular, when an abrasive is contained as an external additive, the wedge accumulates in the wedge-shaped space and polishes the photosensitive drum.

Further, in (2), since the repulsion elasticity is low and the hardness is high at the surface temperature of the photoconductor, the scraping ability for the photoconductor surface is improved as compared with the conventional blade having high repulsion elasticity. It is possible to scrape off the toner fusion.

[0011]

However, the following problems occur when these methods are adopted.

First, it is ideal that the nip portion has a uniform width in the thrust direction and is linear, but in reality, the straightness in the thrust direction of the blade supporting sheet metal and the local friction coefficient of the photosensitive drum. Due to the change of etc., some distortion occurs in the thrust direction. In particular, this strain is remarkable when a blade with low impact resilience having a high peak temperature of tan δ of viscoelasticity is used.

Next, in (1), the polishing action of the photosensitive drum by the abrasive is such that when the blade nip portion is distorted in the thrust direction as described above, the photosensitive drum is unevenly scraped in the thrust direction. Phenomenon occurs. This one-sided scraping easily occurs when the amount of the abrasive in the toner is large. Such shavings become noticeable as the durability increases, and appear as density unevenness in the thrust direction in a halftone image after about 1 million sheets.

On the other hand, in (2), the viscoelastic property tanδ
High blades have reduced rubber elasticity in low temperature environments,
The blade nip width with respect to the photosensitive member becomes unstable, and problems such as poor cleaning and slipping occur. To solve this problem, in order to stabilize the blade nip width, it is conceivable to increase the straightness of the blade supporting sheet metal in the thrust direction, but such a structure causes an increase in the cost of the apparatus.

Therefore, the present invention provides (1) a cleaning system capable of preventing a phenomenon called shaving, which occurs in a system using an a-Si photoreceptor and containing a large amount of an abrasive as a toner, and (2) ) a-Si As a cleaning system for a photoconductor, a cleaning system which does not cause cost increase from the conventional configuration, does not cause toner fusion on the photoconductor, does not cause cleaning failure and does not slip through, and has good cleaning property is provided. The purpose is to provide each.

[0016]

DISCLOSURE OF THE INVENTION The inventors of the present invention have found that the problems associated with the above-mentioned constitutions include the use of urethane rubber as the base material of the cleaning blade, and at least the electrostatic latent image of the cleaning blade. It has been found that the problem can be solved by using a material in which a cured layer is formed by impregnating a portion in contact with a carrier with an isocyanate compound and then heat curing.

That is, in order to achieve the above-mentioned object, the invention according to the present application comprises an electrostatic latent image carrier having an amorphous silicon type photosensitive layer and rotating, and an electrostatic latent image by magnetic and non-magnetic toner. A developing device that visualizes the toner image, a transfer device that transfers the toner image, and a cleaning device that cleans the magnetic and non-magnetic toner remaining on the electrostatic latent image carrier after the transfer, The magnetic and non-magnetic toner in the developing device is such that, at the start of use of the developing device, in the image forming apparatus containing 1.0% by mass or more of an abrasive, the cleaning device is pressed against the rotating electrostatic latent image carrier. And a cleaning blade formed of urethane rubber as a base material. A cured layer is formed by surface-treating the surface with an isocyanate compound, and a cleaning layer is formed by impregnating at least a portion of the cleaning blade in contact with the electrostatic latent image bearing member with the isocyanate compound and then heat curing to form a cured layer. The present invention relates to an image forming apparatus characterized by being a blade.

Further, a rotating electrostatic latent image carrier provided with an amorphous silicon type photosensitive layer, a developing device for visualizing the electrostatic latent image with magnetic and non-magnetic toner to form a toner image, and a toner image In an image forming apparatus having a transfer device for transferring and a cleaning device for cleaning the magnetic and non-magnetic toner remaining on the electrostatic latent image carrier after transfer,
The cleaning device includes a cleaning blade that is brought into pressure contact with a rotating electrostatic latent image carrier. The cleaning blade is made of urethane rubber as a base material, and has a peak temperature of tan δ of viscoelasticity of 1 ± 1. A cleaning blade having a temperature of 10 ° C. is used, and further, a surface of the cleaning blade is subjected to a surface treatment with an isocyanate compound to form a cured layer, and an isocyanate compound is added to at least a portion of the cleaning blade that comes into contact with the electrostatic latent image bearing member. The present invention relates to an image forming apparatus, which is a cleaning blade that is impregnated and then heat cured to form a cured layer.

The present invention focuses on the urethane-bonding group having active hydrogen originally present in polyurethane, and firmly bonds the isocyanate compound and urethane through the allophanate bond, and further, the excess isocyanate that does not react with the active-hydrogen compound. The feature is that the compound is self-polymerized.

According to this method, the surface-hardened layer can be formed by impregnating the isocyanate without impregnating the active hydrogen compound, and the number of steps is smaller than that in the prior art and the cost is low. In addition, the hardened layer can be made thicker and the density of the treatment is higher because no organic solvent is used, so the hardened layer is denser than the conventional technology, the low friction effect is high, and the impregnated hardened layer can be formed deeply. Long wear life due to low friction even when wear progresses.

Further, since the tip of the cleaning blade has low friction and is covered with the hardened layer, deformation by frictional force with an object to be contacted is small, and the edge is covered with the hardened layer. The distortion of the nip portion is reduced, and the linearity of the nip portion is maintained. Further, since the edge always has a sharp shape, the scraping ability with respect to the photoconductor is significantly improved, and the toner fusion can be prevented.

Further, when the external additive contains the abrasive in an amount of 1.0 mass% or more, distortion in the thrust direction of the blade nip portion is reduced, so that uneven scraping in the thrust direction of the photosensitive drum is eliminated and partial scraping can be prevented.

On the other hand, when a cleaning blade having a viscoelastic characteristic tan δ peak temperature of 1 ± 10 ° C. is used as the base material of the cleaning blade, the viscoelastic characteristic tan δ peak temperature of the high repulsion elasticity is low. Therefore, the rubber elasticity is maintained even in a low temperature environment, and the cleaning property can be stably ensured.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an image forming apparatus according to this embodiment.
FIG. 1 is a schematic configuration diagram showing (an image forming apparatus capable of double-sided image formation by a through-pass double-sided method in the present embodiment).

The image forming apparatus shown in FIG. 1 includes a photosensitive drum 1 which is driven to rotate in the arrow direction (clockwise direction) as an image carrier. Around the photosensitive drum 1, a charger 6, an exposure device 7, a developing device 8, a transfer device 9, a cleaning blade 13 and the like are arranged.

Further, a transfer material cassette 10 in which the transfer material P is housed in order from the upstream side in the transfer direction of the transfer material P such as paper with the transfer portion between the transfer device 9 and the photosensitive drum 1 sandwiched, a transfer device 11, A fixing device 12, a reversing roller 14, a re-feeding belt 20 and the like are arranged.

The photosensitive drum 1 has a photosensitive layer of a-Si on a cylindrical substrate made of metal (for example, aluminum),
The surface of the photosensitive drum 1 is rotated by a driving unit (not shown) at a predetermined speed in the arrow direction (clockwise direction), and the charger 6
Is uniformly charged by the discharge. Inside the photosensitive drum 1, a planar heater 2 is arranged for one round. The temperature control of the photosensitive drum 1 by the heating heater 2 is
The temperature is detected by the temperature thermistor 3 of the photosensitive drum 1 heated by the heat-generating heater 2, and the controller 5 controls the power supply from the power source 4 to the heat-generating heater 2 based on the temperature information detected by the thermistor 3. Be seen. Further, the control device 5 controls the power supply from the power source 4 to the heat generating heater 2 based on the environmental temperature / humidity information around the photosensitive drum 1 detected by the temperature / humidity detection sensor 21 to bring the photosensitive drum 1 to a predetermined temperature. Set.

The exposure device 7 performs image exposure according to the input image information on the photosensitive drum 1 charged by the charger 6 to form an electrostatic latent image.

The developing device 8 attaches toner to the electrostatic latent image to visualize it as a toner image.

The transfer device 9 is corona charged in the present embodiment, and the photosensitive drum 1 is provided between the transfer device 9 and the photosensitive drum 1.
The toner image formed on the transfer material P is transferred.

The fixing device 12 has a rotatable fixing roller 12a and a pressure roller 12b which are in contact with each other, and a heater (not shown) is provided in the fixing roller 12a.

The cleaning blade 13 comes into contact with the photosensitive drum 1 and removes transfer residual toner remaining on the surface of the photosensitive drum 1 after transfer.

Next, an image forming operation by the above image forming apparatus will be described.

During double-sided image formation, the photosensitive drum 1 is rotationally driven at a predetermined speed in the arrow direction (clockwise direction) by driving means (not shown), and the surface thereof is uniformly charged by the charger 6. Then, image exposure is performed on the surface of the photosensitive drum 1 in accordance with image information input from the exposure device 7, and charges in the exposed portion are removed to form an electrostatic latent image. This electrostatic latent image is developed with toner attached by the developing device 8 and visualized as a toner image.

When the toner image on the photosensitive drum 1 reaches between the photosensitive drum 1 and the transfer device 9, the transfer material P fed from the transfer material cassette 10 is transferred to this timing by a registration roller (not shown). The toner image on the photosensitive drum 1 is transferred onto the surface (one surface) of the transfer material P by the transfer device 9.

Then, the transfer material P having the toner image transferred on one side is conveyed by the conveying device 11 to the fixing device 12 between the fixing roller 12a and the pressure roller 12b. The transfer material P on which the toner image is transferred is heated and pressed between the fixing roller 12a and the pressure roller 12b to fix the toner image, and then is conveyed onto the re-feeding belt 20 by the reversing roller 14. Then, the transfer material P conveyed onto the re-feeding belt 20 is conveyed again to the transfer portion between the photosensitive drum 1 and the transfer device 9, and is transferred to the other surface on which the toner image is not transferred in the same manner as above. After the image is formed, it is discharged to the outside.

The transfer residual toner remaining on the photosensitive drum 1 is removed by the cleaning blade 13.

At the time of double-sided image formation, as shown in FIG. 2, the transfer material P ₁ having the image A formed on one surface is conveyed by the reversing roller 14 onto the re-feeding belt 20, and the re-feeding belt 20. Is conveyed again to the transfer portion between the photosensitive drum 1 and the transfer device 9, and the image B is transferred to the other surface in the same manner as above.
The double-sided image transfer material P ₂ on which is formed is discharged to the outside. In this way, the transfer material at the time of double-sided image formation is re-conveyed on the re-feeding belt 20 without being temporarily stopped, so that the image forming speed per hour is dramatically improved.

During the one-sided image formation, the transfer material P, which is heated and pressed between the fixing roller 12a and the pressure roller 12b in the same manner as described above and has the toner image fixed on one side, is re-fed by the reversing roller 15. It is discharged to the outside without being conveyed on the belt 20.

Next, the cleaning blade 13 will be described in detail. Cleaning blade in the present invention 13
Is based on polyurethane, which has been conventionally used for electrophotography.

As the polyurethane forming the base material of the cleaning blade of the present invention, those obtained by reacting a polymer polyol, a polyisocyanate and a curing agent can be used. You may use the catalyst normally used for urethane hardening at the time of hardening. The isocyanate group content (NCO%) of the polyurethane resin is preferably 5 to 20% in order to realize good elastic properties.

The blade is molded by a one-shot method in which the above components are mixed at once and cast into a mold or a centrifugal molding cylindrical mold for molding, or an isocyanate and a polyol are reacted in advance to prepare a prepolymer. Then, a prepolymer method in which a cross-linking agent is mixed and cast into a mold or a centrifugal molding cylindrical mold to be molded, or a semi-prepolymer in which isocyanate is reacted with a polyol and a curing agent in which a polyol is added to a cross-linking agent are used. It is possible to use a semi-one-shot method in which the reaction is performed and the mixture is cast into a mold or a centrifugal molding cylindrical mold for molding.

In producing the cleaning blade used in the present invention, the entire or part of the cleaning blade molded as described above is impregnated with an isocyanate compound and cured to form a cured film from the surface of the urethane toward the inside. It is characterized by

In the present invention, the whole or a part of the blade may be impregnated with the isocyanate compound either by the blade member alone or by joining the supporting members.
Moreover, the sheet before cutting the cleaning blade may be used.

When only a portion is to be impregnated, a method of masking a portion which is not desired to be impregnated with a chemical resistant tape or dipping only a portion to be impregnated can be adopted.

The position where the cleaning blade is impregnated with the isocyanate compound is at least the portion where the cleaning blade and the toner carrying member are in contact with each other, and it is better to impregnate the periphery with a margin. This is because there is a possibility that the peripheral portion when stationary will contact the toner carrier when sliding.

As a method of impregnating the blade member with the isocyanate compound, for example, the polyisocyanate compound is brought to a temperature at which it is in a liquid state, and the blade member is immersed therein. Alternatively, a method of applying to a blade in which a fibrous or porous material is impregnated with an isocyanate compound can be adopted. Alternatively, it may be applied by spraying.

Similarly, the temperature of each of the isocyanate compounds during the dipping in the isocyanate liquid, during coating, and after coating is preferably the temperature at which the isocyanate compound is liquid.

In this way, the isocyanate compound is impregnated in the urethane, and after a certain time, the isocyanate compound remaining on the urethane surface is wiped off.

The thickness of the hardened layer obtained by impregnating the blade with isocyanate is preferably 0.12 mm or more.

If the thickness is 0.12 mm or less, the effect on the reduction of the friction coefficient is small, and there may be a problem in wear resistance. Further, since the tip is largely deformed by the frictional force against the contacting object, there may be a problem in cleaning performance for recent minute toner or spherical toner.

The isocyanate compound with which the blade is impregnated has one or more isocyanate groups in the molecule. As the one having one isocyanate group, an aliphatic monoisocyanate such as octadecyl isocyanate or an aromatic monoisocyanate can be used. .

Those having two isocyanate groups are
2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate (MDI), m-phenylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, 4,4 ', 4 "-triphenyl Methane triisocyanate, 2,4 ', 4 "biphenyl triisocyanate, 2,4,4" -diphenylmethane triisocyanate, etc. are used.

It is not particularly limited to these. Further, modified products and multimers of those having three or more isocyanate groups and those having two or more isocyanate groups can be used.

Of these, aliphatic monoisocyanates having less steric hindrance and MDI having a smaller molecular weight are preferred from the viewpoint of permeability.

As the polymerization catalyst used together with the isocyanate compound, a quaternary ammonium salt, a carboxylate or the like can be used. DA as a quaternary ammonium salt
BCO TMR catalysts, NCX211, NCX212 (manufactured by Sankyo Air Products) and the like are used. These catalysts contain a hydroxyl group, but the function is to polymerize the isocyanate, since it does not participate in the cross-linking structure itself, it is a completely different substance from the active hydrogen compound described in JP-A-8-248851. It can be said that there is. As the carboxylate, potassium acetate, potassium octylate (P-15, k-1
5, Sankyo Air Products) and the like are used.

Since these catalysts are very viscous or crystalline when they are not dissolved in a solvent, it is preferable to add them to the isocyanate compound after dissolving them in the solvent. As the diluting solvent, a solvent having no active hydrogen that reacts with isocyanate is preferable. Specifically, MEK,
Toluene, tetrahydrofuran, ethyl acetate and the like can be used. The dilution ratio is preferably about 1.5 to 10 times.

The addition rate of the catalyst to the isocyanate compound is preferably 1 ppm to 1000 ppm.

Further, when a catalyst is mixed with isocyanate, the polymerization reaction is promoted. Therefore, it is preferable to mix the catalyst immediately before impregnation. The temperature of the isocyanate compound when impregnating, the lower limit may be a liquid, in order to prevent the isocyanate compound from deteriorating during the treatment of the upper limit,
90 ° C is preferable.

The surface of the blade is impregnated or coated with an isocyanate compound for a few minutes to a few hours, the excess isocyanate is wiped off, and then heat treatment is carried out in an atmosphere of 50 to 140 ° C. for a few minutes to several hours. There is a urethane bond having active hydrogen in the structure of polyurethane, which can react with an isocyanate group. That is, it reacts with the active hydrogen of the urethane group in the polyurethane to form an allophanate bond and forms a three-dimensional branched structure.

An isocyanate compound having two or more isocyanate groups undergoes a polymerization reaction by a urea bond mediated by water in the environment to form a network structure together with the above three-dimensional branched structure, and a cured layer is formed. It is formed.

With the use of the polymerization catalyst, the polymerization reaction also progresses due to its action. This reaction does not require moisture in the environment, and the isocyanate groups react with each other, so that the reaction is characterized by being completed quickly.

Further, since the crosslinked structure is formed by the trimerization reaction, the strength of the cured film is high and a cleaning blade having good durability can be manufactured.

In the isocyanate compound having one isocyanate group, when the isocyanate group reacts with the urethane group to revise the allophanate bond, the free end is oriented toward the outside of the polyurethane surface. Friction can be reduced, avoiding contact.

The impregnating property is preferably such that the molecular weight is small, and it is easy to form a cured film having a high isocyanate density. Further, it is possible to control from a thin film thickness to a thick film thickness.

A polymer having a large molecular weight has a poor impregnation property but is a long chain, so that the molecular chains are projected from the surface of polyurethane, and the thickness of the cured layer is relatively thin, but it is effective in reducing the frictional force. is there.

[0068]

EXAMPLES Example 1 In the present embodiment, the photosensitive drum 1
As the material, an a-Si drum having a diameter of 108 mm was used.

Here, the toner will be described in detail. The toner used in this embodiment has a negatively charged average particle size of about 9 μm.
m, main binder is styrene acrylic, magnetic material is about 80
In one part by mass, a one-component magnetic toner having a glass transition point of about 60 ° C., which is obtained by externally adding 0.5 mass% of silica as an external additive and 4.0 mass% of strontium titanate as an abrasive, is used. Tribo on the sleeve is -3 to -12 (μC / g).

In this example, a 3 mm thick cleaning blade (having a peak temperature of tan δ of viscoelasticity of 7 ° C.) made of urethane having a hardness of JIS 70 degrees and made of thermosetting polyester polyurethane was used. Masked with chemical resistant tape as shown in 5 and put in MDI bath at 80 ℃ 1
It was immersed for 0 minutes, the excess isocyanate was wiped off to remove the masking, and it was cured in an oven at 130 ° C for 60 minutes.

A PET film sheet with this cleaning blade cut into a width of 50 mm was counter-contacted with a HEIDO sheet at a weight of 30 g / 1 cm and a moving speed of 10 cm / min.
The friction coefficient measured by the N surface property tester was 0.9.

When the cross section was observed with a microscope, the cured part was clouded and the thickness of the cured film was 0.25 mm.

The viscoelastic characteristics of the test piece for measuring viscoelastic characteristics (thickness 1 mm) were compared with those before the processing.

As can be seen from this figure, the viscoelastic characteristics
The peak temperature of tan δ is higher after treatment and is closer to the surface temperature of the photoconductor (about 40 ° C).
Further, the value of tan δ near the surface temperature of the photoconductor is high, and at this temperature, the impact resilience is low and the hardness is high.

Further, as shown in FIG. 3, the pressing direction of the cleaning blade remains the urethane rubber layer of high repulsion resilience in which the peak temperature of tan δ before processing is low, and therefore the pressing stability of the cleaning blade is improved. Can get
The width of the nip portion in the thrust direction becomes stable.

The cleaning blade 13 manufactured as described above was attached to the image forming apparatus shown in FIG.
A 10,000-sheet copy test was conducted. As a result, density unevenness due to one-side scraping did not occur in the halftone image.

On the other hand, when a conventional cleaning blade in which the edge portion was not processed was subjected to a copy test in the same manner, uneven density due to one-side scraping occurred.

As described above, since the edge of the cleaning blade used in the present invention has low friction and is covered with the hardened layer, it is less likely to be deformed by the frictional force with the contact object (photosensitive drum). Since the edge is covered with the hardened layer, distortion of the blade nip portion is small and the linearity of the nip portion is maintained, so that there is no unevenness in the thrust direction of the photosensitive drum.

Furthermore, in this embodiment, as shown in FIG. 3, since the high repulsion elastic layer which can provide the pressing stability in the pressing direction of the cleaning blade is obtained, the stability of the blade nip in the thrust direction is further increased.

(Embodiment 2) In the first embodiment, the negatively chargeable magnetic toner is used as the toner, but the same effect can be obtained even when the positively chargeable magnetic toner is used. Examples of positively chargeable magnetic toner include
It can be used as an example.

Styrene-butyl methacrylate-dimethylaluminoethyl methacrylate (mass ratio 7: 2.5: 0.5) copolymer 100 parts by mass, BET surface area 5 m ² / g and Mohs hardness 5.
No. 5 magnetite 40 parts by weight, and weight average molecular weight 1500
At 0, 3 parts by mass of polypropylene having a boiling point of n-hexane and a content of 20% by mass extracted were mixed and melt-kneaded at 160 ° C. in a roll mill. After cooling, it was roughly crushed with a hammer mill and then finely crushed with a jet crusher. Then, classification was performed using an air classifier to obtain a black fine powder having a volume average particle diameter of about 7.5 μm as a black magnetic toner.

On the other hand, fine silica powder synthesized by the dry method
(Specific surface area: approx. 130 m ² / g) 12 parts by mass of silicone oil having a side chain with amine (viscosity 70 mPa · s at 25 ° C, amine equivalent 830) with 100 parts by mass is stirred and maintained at a temperature of approx. 250 ° C. And processed for 60 minutes. The hardness of this silica was 6.0 in Mohs' hardness.

To the magnetic toner, 0.8 mass% of silica fine powder treated with silicone oil having amine in the above side chain and 1.0 mass% of strontium titanate are externally added to form a positively charged magnetic toner. is there.

As described above, by using the positively chargeable magnetic toner, the present invention can be applied to the image forming apparatus which performs the digital reversal development on the a-Si photoconductor, and the digital method using the laser light is used. It can also be applied to electrophotographic copying machines.

(Example 3) In Examples 1 and 2, strontium titanate was used as the polishing agent externally added to the toner, but cerium oxide can also be used as the polishing agent. In this case, the polishing effect on the surface of the photosensitive drum is further improved, and the toner fusion and the filming phenomenon can be further suppressed.

(Embodiment 4) In Embodiments 1 to 3, magnetic toner is used as toner, but non-magnetic toner may be used. In this case, in addition to the effects described in the first embodiment, the present invention can be applied to a multicolor image forming apparatus such as a color copying machine using an a-Si photoconductor.

(Fifth Embodiment) Further, in the present invention, as the cleaning device, in addition to the cleaning blade, a device provided with a cleaning roller as shown in FIG. 4 may be used. The cleaning roller is installed on the upstream side of the cleaning blade in the rotation direction of the photoconductor for the purpose of stably supplying the toner to the cleaning blade, scrapes the residue on the photoconductor by rubbing, and applies toner to the photoconductor. In this case, the cleaning property is further stabilized in addition to the effect described in the first embodiment.

(Embodiment 6) Further, according to the present invention, as a cleaning device, a cleaning blade is configured to reciprocate in its longitudinal direction with an appropriate stroke.
(Also called reciprocal mechanism) can be applied. Since the reciprocating rubbing of the blade in such a short time is repeatedly rubbed, unevenness in the longitudinal direction of the polishing action due to the abrasive accumulated in the wedge-shaped space immediately before the nip portion of the cleaning blade is reduced, and the uneven scraping phenomenon is further prevented. You can

Next, examples of effects on toner fusion will be described.

(Example 7) The toner used in the present invention is a magnetic toner (toner having magnetism), and 100 parts by mass of a styrene-butyl methacrylate-dimethylaluminoethyl methacrylate (mass ratio 7: 2.5: 0.5) copolymer is used. , 40 parts by weight of magnetite having a BET surface area of 5 m ² / g and a Mohs hardness of 5.5,
And boiling point n-hexane extract with a weight average molecular weight of 15,000 20
3 parts by mass of polypropylene having a mass percentage was mixed and melt-kneaded at 160 ° C. in a roll mill. After cooling, it was roughly crushed with a hammer mill and then finely crushed with a jet crusher. Then, classification was performed using an air classifier to obtain a black fine powder having a volume average particle diameter of about 7.5 μm as a black magnetic toner.

On the other hand, silica fine powder synthesized by the dry method
(Specific surface area: approx. 130 m ² / g) 12 parts by mass of silicone oil containing amine in the side chain (viscosity 70 mPa · s at 25 ° C, amine equivalent 830) with 100 parts by mass is stirred and maintained at a temperature of approx. 250 ° C. And processed for 60 minutes. The hardness of this silica was 6.0 in Mohs' hardness.

100 parts by weight of magnetic toner, silica fine powder treated with silicone oil having amine in the above side chain
0.4 parts by mass and 0.05 parts by mass of polyvinylidene fluoride (P
VDF) was added externally to obtain a positively chargeable magnetic toner.

The base material and molding method of the cleaning blade 13 are the same as in the first embodiment.

In this example, the process of forming the cured film of the blade was the same as in Example 1. Specifically, the hardness JIS produced from thermosetting polyester polyurethane
Cleaning blade of 3mm thickness made of 70 degree urethane (peak temperature of tan δ of viscoelastic property is 7 ° C)
Masked with chemical resistant tape as shown in Fig.
It was immersed in the MDI bath for 10 minutes, the excess isocyanate was wiped off, the masking was removed, and it was cured in an oven at 130 ° C for 60 minutes.

When the cross section was observed with a microscope, the cured part was clouded and the thickness of the cured film was 0.8 mm.

Further, the result of comparing the viscoelastic characteristic of the test piece for measuring viscoelastic characteristic (thickness 1 mm) with that before treatment was the same as that of Example 1 because the base material was the same. (See FIG. 2).

Further, as shown in FIG. 6, the pressing direction of the cleaning blade remains the urethane rubber layer of high impact resilience having a low peak temperature of tan δ before the treatment, so that the pressing stability of the cleaning blade is obtained. Therefore, the nip width becomes stable, and the cleaning property becomes good.

The cleaning blade 13 manufactured as described above was attached to the image forming apparatus shown in FIG.
A copying test of 400,000 sheets was performed in an environment of 30 ° C. and humidity of 80% RH (high temperature and high humidity). As a result, toner fusion, poor cleaning, and slip-through did not occur.

On the other hand, when a conventional cleaning blade in which the edge portion was not processed was subjected to a copy test in the same manner, toner fusion occurred on about 300,000 sheets.

As described above, according to the present invention, the edge portion of the cleaning blade that comes into contact with the photosensitive drum 1 is a low repulsion elastic layer having a high scraping ability, and the stability of pressing is obtained in the pressing direction of the cleaning blade. Since the high impact resilience layer is used, toner fusion does not occur and a cleaning system having good cleaning properties can be obtained.

(Embodiment 8) In Embodiment 7, a positively chargeable magnetic toner is used as the toner, but the same effect can be obtained by using a negatively chargeable magnetic toner. As the negatively chargeable magnetic toner, the average particle size was about 9 μm, the main binder was about 80 parts by mass of the styrene acrylic magnetic material, and 4% of strontium titanate and 0.5% of silica were used as external additives.
A one-component magnetic toner having a glass transition point of about 60 ° C. can be used, and the tribo on the developing sleeve of this toner is −3 to −12.
(μC / g). As described above, the present invention can be applied to an analog copying machine using an a-Si photoconductor as a photosensitive drum by using the negatively chargeable magnetic toner.

(Embodiment 9) Further, in the present invention, as the cleaning device, in addition to the cleaning blade, a device provided with a cleaning roller as shown in FIG. 4 may be used. The cleaning roller is installed on the upstream side of the cleaning blade in the rotation direction of the photosensitive member for the purpose of stable supply of toner to the cleaning blade, and scrapes off the residue on the photosensitive member by rubbing and applies toner to the photosensitive member. In this case, in addition to the effect described in Example 7, the cleaning property becomes more stable.

[0103]

As described above, according to the present invention,
Since the edge of the cleaning blade has low friction,
The blade is less deformed by friction with the photosensitive drum, and the edge portion is covered with the hardened layer, so that the blade nip portion is less distorted and the linearity in the thrust direction of the nip portion is maintained. From the above, in the polishing action of the photosensitive drum by the abrasive contained in the toner, uneven polishing (shaving unevenness) in the thrust direction of the photosensitive drum is eliminated, and the one-sided phenomenon can be prevented.

Further, according to the present invention, as a cleaning system for an a-Si photosensitive member, toner fusion on the photosensitive member does not occur without increasing the cost of the structure of the conventional cleaning device, and cleaning failure and slip-through occur. It was possible to provide an image forming apparatus having a cleaning system with good cleaning properties.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram illustrating an image forming apparatus according to first and seventh embodiments of the present invention.

FIG. 2 is a diagram showing viscoelastic characteristics of a cleaning blade used in the present invention.

FIG. 3 is a diagram showing a nip portion between a cleaning blade and a photosensitive drum in Embodiment 1 of the present invention.

FIG. 4 is a schematic configuration diagram showing an image forming apparatus according to embodiments 5 and 9 of the present embodiment.

FIG. 5 is a diagram showing a cured layer forming process in Examples 1 and 7 of the present invention.

FIG. 6 is a diagram showing a contact amount of a cleaning blade with a photoconductor according to a seventh embodiment of the present invention.

[Explanation of symbols]

1 photosensitive drum 2 heating heater 6 charger 7 Exposure equipment 8 developing device 9 Transfer device 11 Transport device 12 Fixing device 13 cleaning blade 15 cleaning roller

Claims (14)

[Claims] 1. A rotating electrostatic latent image carrier provided with an amorphous silicon-based photosensitive layer, and a developing device which visualizes the electrostatic latent image with magnetic and non-magnetic toner to form a toner image.
The magnetic and non-magnetic toner in the developing device has a transfer device for transferring the toner image and a cleaning device for cleaning the magnetic and non-magnetic toner remaining on the electrostatic latent image carrier after transfer. An image forming apparatus containing an abrasive in an amount of 1.0 mass% or more at the start of use of the developing device, wherein the cleaning device includes a cleaning blade that is brought into pressure contact with a rotating electrostatic latent image bearing member. Is a cleaning blade formed of urethane rubber as a base material, and further, a cured layer is formed by surface-treating the cleaning blade surface with an isocyanate compound,
An image forming apparatus comprising a cleaning blade in which at least a portion of the cleaning blade that comes into contact with the electrostatic latent image bearing member is impregnated with an isocyanate compound and then cured by heating to form a cured layer. 2. The cleaning blade is formed by impregnating at least a portion of the cleaning blade member, which is in contact with the electrostatic latent image bearing member, with an isocyanate compound together with an isocyanate polymerization catalyst and then heat-treating it to form a cured layer from the surface to the inside. The image forming apparatus according to claim 1, wherein the image forming apparatus is formed. 3. The cleaning blade, wherein at least a portion of the cleaning blade member that comes into contact with the electrostatic latent image bearing member is impregnated with an isocyanate compound and then heat-treated, and a cured layer having a film thickness of 0.12 mm or more from the surface to the inside. The image forming apparatus according to claim 1, wherein the image forming apparatus is formed. 4. An electrostatic latent image carrier having an amorphous silicon photosensitive layer and rotating, and a developing device which visualizes the electrostatic latent image with magnetic and non-magnetic toner to form a toner image.
The magnetic and non-magnetic toner in the developing device has a transfer device for transferring the toner image and a cleaning device for cleaning the magnetic and non-magnetic toner remaining on the electrostatic latent image carrier after transfer. An image forming apparatus containing an abrasive in an amount of 1.0 mass% or more at the start of use of the developing device, wherein the cleaning device includes a cleaning blade that is brought into pressure contact with a rotating electrostatic latent image bearing member. Uses a cleaning blade made of urethane rubber as a substrate, and impregnate at least a portion of the cleaning blade member that comes into contact with the electrostatic latent image carrier with an isocyanate compound containing at least a monofunctional isocyanate compound. After that, it is a cleaning blade that has been heat treated to form a hardened layer from the surface to the inside. An image forming apparatus characterized by. 5. A rotating electrostatic latent image carrier having an amorphous silicon type photosensitive layer, and a developing device which visualizes the electrostatic latent image with magnetic and non-magnetic toner to form a toner image.
The magnetic and non-magnetic toner in the developing device has a transfer device for transferring the toner image and a cleaning device for cleaning the magnetic and non-magnetic toner remaining on the electrostatic latent image carrier after transfer. An image forming apparatus containing an abrasive in an amount of 1.0 mass% or more at the start of use of the developing device, wherein the cleaning device includes a cleaning blade that is brought into pressure contact with a rotating electrostatic latent image bearing member. Is a cleaning blade formed of urethane rubber as a substrate, further, the cleaning blade by applying a isocyanate compound together with an isocyanate polymerization catalyst part or all of the elastic sheet before cutting the cleaning blade After impregnation treatment, heat treatment is performed to form a hardened layer from the surface to the inside, and then a clear layer is formed. An image forming apparatus, which is a cleaning blade cut into the shape of a burning blade. 6. The cleaning blade used as the base material has a peak temperature of tan δ of viscoelasticity of 1 ± 1.
It is 10 degreeC, The image forming apparatus in any one of Claims 1-5 characterized by the above-mentioned. 7. The image forming apparatus according to claim 1, wherein the abrasive contained in the magnetic and non-magnetic toner in the developing device is strontium titanate. 8. A rotating electrostatic latent image carrier having an amorphous silicon type photosensitive layer, and a developing device which visualizes the electrostatic latent image with magnetic and non-magnetic toner to form a toner image.
In an image forming apparatus having a transfer device for transferring a toner image and a cleaning device for cleaning the magnetic and non-magnetic toner remaining on the electrostatic latent image carrier after transfer, the cleaning device is a The cleaning blade is provided in pressure contact with the latent image carrier, and the cleaning blade is formed of urethane rubber as a base material, and has a peak temperature of tan δ of viscoelasticity of 1 ± 10 ° C. Furthermore, a cured layer is formed by surface-treating the surface of the cleaning blade with an isocyanate compound. At least a portion of the cleaning blade that comes into contact with the electrostatic latent image carrier is impregnated with the isocyanate compound and then cured by heating. An image forming apparatus comprising a cleaning blade having a layer formed thereon. 9. The cleaning blade is formed by impregnating at least a portion of the cleaning blade member, which is in contact with the electrostatic latent image bearing member, with an isocyanate compound together with an isocyanate polymerization catalyst, and then by heat treatment to form a cured layer from the surface to the inside. The image forming apparatus according to claim 8, wherein the image forming apparatus is formed. 10. The cleaning blade, wherein at least a portion of the cleaning blade member that comes into contact with the electrostatic latent image carrier is impregnated with an isocyanate compound and then heat-treated, and a cured layer having a film thickness of 0.12 mm or more from the surface to the inside. The image forming apparatus according to claim 8, wherein the image forming apparatus is formed. 11. A rotating electrostatic latent image carrier having an amorphous silicon type photosensitive layer, a developing device for visualizing the electrostatic latent image with magnetic and non-magnetic toner to form a toner image, and a toner image An image forming apparatus having a transfer device for transferring and a cleaning device for cleaning magnetic and non-magnetic toner remaining on the electrostatic latent image carrier after transfer, wherein the cleaning device is a rotating electrostatic latent image carrier. A cleaning blade that is pressed against the body is used. The cleaning blade is made of urethane rubber as a base material, and has a peak temperature of tan δ of viscoelasticity of 1 ± 10 ° C. Isocyanate compound containing at least a monofunctional isocyanate compound in at least a portion of the cleaning blade member in contact with the electrostatic latent image carrier An image forming apparatus, wherein the cleaning blade is a cleaning blade in which a hardened layer is formed from the surface to the inside by impregnating and then heat-treating. 12. A rotating electrostatic latent image carrier having an amorphous silicon type photosensitive layer, a developing device for visualizing the electrostatic latent image with magnetic and non-magnetic toner to form a toner image, and a toner image. An image forming apparatus having a transfer device for transferring and a cleaning device for cleaning magnetic and non-magnetic toner remaining on the electrostatic latent image carrier after transfer, wherein the cleaning device is a rotating electrostatic latent image carrier. A cleaning blade that is pressed against the body is used. The cleaning blade is made of urethane rubber as a base material, and has a peak temperature of tan δ of viscoelasticity of 1 ± 10 ° C. The cleaning blade uses an isocyanate compound as an isocyanate polymerization catalyst for a part or all of the elastic sheet before cutting the cleaning blade. An image forming apparatus comprising a cleaning blade which is impregnated by coating together and then heat-treated to form a cured layer from the surface to the inside and then cut into a cleaning blade shape. 13. The image forming apparatus according to claim 8, wherein the cleaning device is provided with a cleaning roller in addition to the cleaning blade. 14. The image forming apparatus according to claim 13, wherein the cleaning roller includes a magnetism generating means.